Platinum is a dense metal, which is ductile and resistant to high temperature corrosion and oxidation. The properties of platinum make this metal useful in many applications. For example, platinum and platinum alloys are frequently used in the electrical arts for electronic circuits, the chemical arts for catalysts and electrodes, as well as the optical arts for high reflectivity mirrors.
Platinum containing materials also are particularly advantageous for use in high temperature and corrosive environments, such as gas turbine engine operation. In particular, electroplating processes may be employed to deposit a thin layer of platinum on a component prior to diffusion and aluminizing during the production of platinum modified aluminide diffusion coatings.
Chemical vapor deposition processes also may employed to co-deposit platinum with aluminum, as described in commonly assigned U.S. Pat. No. 5,494,704. This patent discloses a useful method to deposit a homogenous biphase mixture of aluminum and platinum on a substrate, such as turbine hardware, by low temperature chemical vapor deposition, thereby providing coverage of internal and external areas of substrate.
However, some prior platinum coating processes suffer from poor deposition uniformity and an undesirable amount of impurities present in the resulting coating after electroplating; platinum losses in the CVD deposition reactor; and inability to produce pure, high temperature platinum coatings. Moreover, current deposition processes for platinum-containing materials often require large capitalization equipment and may not achieve the level of performance needed for some high temperature applications.
Accordingly, there exists a need for a process of depositing pure platinum, which is cost effective, size insensitive and results in uniform deposition of the coating.